Production of diolefins



Ligh? Ends @mcd-0M M. SINGLETGN PRODUCTION 0F DIOLEFINS Filed Feb. 15, 1943 @mediano Piperylno Polymw Arrofwfr:

Patented Ang. 14, 1945 l l r v2,382,749

UNITED STATE-S PATENT oFFIcE PnonUc'rioN oF nIoLEFxNs v A Henry M. Singleton, vGoose Creek, Tex., assignor poration of Delaware l Application February 15, 1943, Serial No. 475,867

3Ulaims.

The present invention is directed to a method for producing dioleilns from heterocyclic. ring I compounds containing conjugated double bonds.

According to the present invention dioleiins are prepared by subjecting an organic compound of the type generally referred to above to hydrogenation under conditions suitable for breakingV vthe ring structure of the compounds. 'I'he ring catalyst a splitting component, such asfmetallic copper or other free metal. The reaction may be promoted by the addition to the reaction mixture of a small amount of an acidic substance, such as hydrochloric acid or similar inorganic acid, which may be injected into the feed line to the catalytic chamber Itispreferred-tous-eafairlyhishpressurein` the reaction chamber. Preferably, the pressure is supplied in the form of partial pressure of hydrogen, although, if desired,inert gases may be included in the reaction mixture ifit is desired to use a low partial pressure of hydrogen.

Standard Oil Development Company, a-corabout 1100 and 1300," F.y and ture passedthrough it rather rapidly. A contact time of one-half to thirty seconds under these .conditions yields satisfactory results. .The reaction chamber can be suddenly chilled by being subjected to a spray of cold liquid. Ii' desired. theV fresh feed may be used asjthe chilling liquid.

The'nature and objects of the present invention will be more readily understood from the following detailed description 'oi'. the accompanying drawing, in which the single ngure is a iront elevation, in diagrammatic form, 4offone type of I apparatus which may be utilized. in 'the practice of thepresent invention. l y

Referring to the drawingin detail, numeral I indicates a reaction vessel'in which thehydrogenation step. of the present invention is performed. As will'be understood, this vessel is provided with a suitable packing o f catalytic material, which may be arranged in any of the -ways well known in the art toprovide'the most eillcient contact time between the catalyst and, the reactants. Hydrogen is introduced into this vessel through line 2.

The eillueni; from the hydrogenation vessel l is discharged into a sprayltower I, into the top Typical examples of organic compounds which may be employed in the process of the present invention are furan. thiophene, and pyrrolc, and derivatives of these compounds in which the con- .iusated double hond linkage is preserved. Compounds which are readily available and are satisfactory for use are furfuraldehyde and furfuryl alcohol.

The most difncult part of the conversion process involved is the splitting out from the ring compound of the element other than carbon and hydrogen in the three speciilc examples referred to.

The hydrogen will combine readily with this ele-- of which the organic compound'to be hydro- Y genated, as for example, furfural, is sprayed in liquid form through line l. ri'he tower 3 will preferably be provided with internal equipment toinsurethoroughmixingof the gaseous eiiiuent from vessel I and the fresh seed. The C-liand heavier hydrocarbons condense inthe tower 3 and pass out of the bottom thereof with the furfural'through line l, while the lighter constituents, including the residual hydrogen, leave the topof tower l through line '8, Vby which theyare returned to the feed line 2. Ii' desired, some of these light ends may be bled oi! through line 1. 'lhe mixture carried by line I is discharged into a fractionating tower l which is so operated that lthe desired dioleflns are recovered overhead ment, which is either atomic oxygen, atomic sulfur, or the radical NH. Therefore. it is preferred to conduct the reaction on the shock principle,

which means that the compound, in adm ixture with hydrogen, is suddenly subjected to rigorous conditions, allowed to remain under these conditions forashorttime,mdthenquicklyrestored to milder conditions. Thus, the reaction chamber Y are recovered as bottoms through line I3.

may be observed at this point that tower Il ma! through line l. In this case the oleiins produced are butadiene and piper'ylene. The residue is removed from tower l asbottomsbyline I, which conducts this residue to a second fractionatin tower Il, which is so operated that furfural and everything boiling lower than it passes of! overhead through line I2, while polymeric compound:

be omitted entirely from thesystem if desired, its onlypin'poeebeingtoreducc'cokinginthe hydrogenctlon lone. Line l! 'carries the overmny be maintained at s temperature between mm: from tower Il backtoifea une 2wnere thereaction mix- The nature and objects of the present invention having been thus described and illustrated, what is claimed as new and useful and is desired to be secured by .Letters Patent is:

1. A method for producing a dioletin which comprises subjecting a heterocyclic compound of the Iuran series to a temperature between 800 F.' and 1400 F. to the action of a dehydrogenation catalyst in the presence of an excess of hydrogen and a small amount of an acidic substance for a period between 0.5 and 30 seconds to effect scission of the ring structure and recovering by distillation of the resulting product a dioleiln having atleast four carbon atoms inthe molecule.

manana 2. A method for producing diolennsirom heterocyclic organic compound of the furan series having a conjugated double bond linkage which comprises subjecting the compound to the action of a dehydrogenation catalyst at a temperature between about 1100 and 1300 F. in the presence of an excess of hydrogen and a small amount of an acidic substance for a period hetween .5 and 30 seconds to eiiect scission of the 'ring structure, shock-chilling. the reaction mixture at the end of the reaction period and recovering a diole'n having atleast four carbon atoms in its molecule from the shock-chilled mixture.

3. A method according to claim 2 in which the catalyst contains a free metal capable oi' catalyzing the cracking of hydrocarbons.

HENRY M. SINGLE'ION. 

